Trading resumes at Chicago exchange

The Chicago Board Options Exchange said trading resumed floor-wide in equity and index options as of 11:37 a.m., with the remaining 125 option classes up and trading by early afternoon.

A database problem had halted all trading at about 9:20 a.m., according to a statement.

Options on the S&P 100, S&P 500, Dow Jones Industrial Average Index and DIAMONDS opened for trading at 9:50 a.m. Trading on options on the Nasdaq 100 Index, iShares Russell 2000 Index Fund and the Nasdaq-100 Index Tracking Stock opened at 10:23 a.m., according to a statement.

The exchange is the world's largest options marketplace and creator of listed options. It is regulated by the Securities and Exchange Commission.